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Biomedical subjects

M Stanley

Publications and source records attributed to M Stanley.

At least 181 records · Page 10Linked to original sources
PubMed1980

Experimental dystonia induced by quaternary-chlorpromazine.

When quaternary-chlorpromazine (Q-CPZ) was administered intraventricularly (ICV) to rats, it induced a lateralized dystonic reaction, which progressed to head-to-tail barrel rolling. The syndrome persisted for approximately 10 minutes, was not antagonized by pretreatment with drugs used to treat extrapyramidal movement disorders, and could not be mimicked by ICV administration of dopamine antagonists. Unlike known dopamine antagonists, Q-CPZ does not alter dopamine turnover, cause prolactin release in vivo, or bind to dopamine/neuroleptic receptors in vitro. These data suggest that Q-CPZ differs substantially from CPZ in pharmacologic action, and that it elicits a behavioral syndrome of potential use for studying dystonias.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

Atypical antidopaminergic properties of CI-686: a potential antipsychotic agent.

The effects of the antipsychotic/antidepressant drug CI-686 on apomorphine- and amphetamine-induced stereotypies, dopamine metabolism, neuroleptic binding, and serum prolactin levels were determined. CI-686 displayed profiles of activity in each of these systems that differs markedly from those of other antipsychotics. CI-686's unique preclinical profile suggests a mechanism of action other than dopamine antagonism which could have implications regarding current thinking on the pathophysiology of schizophrenia.

Amphetamine↗
PubMed1978

Clozapine concentrations in brain regions: relationship to dopamine metabolite increase.

Levels of clozapine in rat striatum and tuberculum olfactorium were quantitated by a gas chromatographic technique. The relationship of the increase in 3,4-dihydroxyphenylacetic acid (DOPAC) in these regions produced by clozapine to the concentration of clozapine was explored. One hour after 10, 20 or 40 mg/kg clozapine i.p. the concentration of drug increased in proportion to the dose and at each dose was similar in striatum and T.O. The percent increase in DOPAC in both areas was related to the clozapine concentration in a typical dose--response manner and was greater in the striatum than the T.O. A relatively high concentration of clozapine (40 micron) was required to produce a half-maximal elevation of DOPAC. Striatal clozapine levels were similar in acutely and chronically treated animals. The concentrations of clozapine in striatum and T.O. reflect the dose injected and do not account for its atypical properties.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1978

Dopamine metabolites in human brain.

The relationship of human brain levels of 3,4-dihydroxyphenylacetic acid (DOPAC) to cerebrospinal fluid levels of this domapine (DA) metabolite was studied. The effect of postmortem delay was evaluated in the rat. DOPAC was resistant to postmortem changes in brain kept in situ. The level of DOPAC (free and conjugated) determined in DA-rich areas of six human brains amounted to only a fraction of the homovanillic acid (HVA) found in the same regions. The DOPAC/HVA ratio in human brain was similar to that found in CSF. We conclude that HVA is the major DA metabolite in human brain and that DA metabolite levels in CSF reflect DA metabolite levels in brain.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1978

Thiethylperazine; clinical antipsychotic efficacy and correlation with potency in predictive systems.

A one-to-one relationship between clinical antipsychotic potency and pharmacologic dopaminergic antagonism is implicit in the dopamine hypothesis of neuroleptic action. Thiethylperazine maleate, a classical antiemetic phenothiazine, displays dopaminergic antagonism in behavioral, neurochemical, and neuroendocrine systems, but is paradoxical insofar as it is thought not to possess clinical neuroleptic activity. In three tests of dopaminergic antagonism--elevation of levels of CSF homovanillic acid in monkeys, striatal dihydroxyphenylacetic acid in rats, and prolactin in man--as well as in a clinical trial of neuroleptic efficacy in schizophrenics, thiethylperazine was fully active and approximately three times as potent as chlorpromazine. Differences in efficacy between this and earlier clinical studies can be accounted for on the basis of dosage.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1977

The effect of antipsychotic drugs and their clinically inactive analogs on dopamine metabolism.

Changes in dopamine metabolite levels in the rat striatum and tuberculum olfactorium, following the administration of three non-antipsychotic butyrophenones (AL-499, AHR-1900 and U-25,927) and a non-antipsychotic benzazepine (SCH-12,679), were compared to the effects seen following the antipsychotics haloperidol, chlorpromazine and clozapine. The non-antipsychotics, although clinically ineffective, were reported as active in a variety of animal screening tests. Haloperidol, chlorpromazine and clozapine produced a dose-dependent increase in 3,4-dihydroxyphenylacetic acid (DOPAC) levels in both regions. Of the non-antipsychotic drugs only AHR-1900 significantly elevated the level of DOPAC, however, the slope of its dose-response curve was atypically flat in comparison to the dose-response curves of drugs with known antipsychotic efficacy. Moreover, the maximal effect of AHR-1900 observed at a dose of 40 mg/kg was less than the ED50 effect of haloperidol which occurs at a 250 fold lower dose. It is concluded that the dose-dependent elevation of DOPAC in the striatum and tuberculum olfactorium of the rat is a good predictor of antipsychotic efficacy.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1977

Perlapine and dopamine metabolism: prediction of antipsychotic efficacy.

A model for the prediction of antipsychotic efficacy based on the dose-dependent increase in levels of 3,4-dihydroxyphenylacetic acid (DOPAC) in the striatum and tuberculum olfactorium of the rat is presented. The effect of perlapine, a sleep-promoting and sedative agent reported to lack antipsychotic efficacy, was compared in this system to haloperidol, chlorpromazine and clozapine. All four drugs produced a dose-dependent increase in DOPAC in the two dopamine-rich structures. The potency of perlapine was similar to that of chlorpromazine. Dopamine, assayed in the striatum and tuberculum olfactorium by a new gas chromatographic procedure was not altered by perlapine. The time--action curves for perlapine and clozapine were virtually identical both in the striatum and in the tuberculum olfactorium. All four drugs also elevated homovanillic acid to a similar extent. These results indicate that perlapine should be re-evaluated clinically. We predict that such trials will reveal that perlapine does possess antipsychotic efficacy.

Animals↗